Index: lib/Serialization/ModuleManager.cpp
===================================================================
--- lib/Serialization/ModuleManager.cpp
+++ lib/Serialization/ModuleManager.cpp
@@ -363,19 +363,6 @@
 
   VisitState *State = allocateVisitState();
   unsigned VisitNumber = State->NextVisitNumber++;
-
-  // If the caller has provided us with a hit-set that came from the global
-  // module index, mark every module file in common with the global module
-  // index that is *not* in that set as 'visited'.
-  if (ModuleFilesHit && !ModulesInCommonWithGlobalIndex.empty()) {
-    for (unsigned I = 0, N = ModulesInCommonWithGlobalIndex.size(); I != N; ++I)
-    {
-      ModuleFile *M = ModulesInCommonWithGlobalIndex[I];
-      if (!ModuleFilesHit->count(M))
-        State->VisitNumber[M->Index] = VisitNumber;
-    }
-  }
-
   for (unsigned I = 0, N = VisitOrder.size(); I != N; ++I) {
     ModuleFile *CurrentModule = VisitOrder[I];
     // Should we skip this module file?
Index: test/Modules/Inputs/builtins/a.h
===================================================================
--- /dev/null
+++ test/Modules/Inputs/builtins/a.h
@@ -0,0 +1,3 @@
+#include <float.h>
+@interface A
+@end
Index: test/Modules/Inputs/builtins/b.h
===================================================================
--- /dev/null
+++ test/Modules/Inputs/builtins/b.h
@@ -0,0 +1,3 @@
+#include "a.h"
+@interface B : A
+@end
Index: test/Modules/Inputs/builtins/module.modulemap
===================================================================
--- /dev/null
+++ test/Modules/Inputs/builtins/module.modulemap
@@ -0,0 +1,7 @@
+module A {
+  header "a.h"
+}
+
+module B {
+  header "b.h"
+}
Index: test/Modules/builtins-incremental.m
===================================================================
--- /dev/null
+++ test/Modules/builtins-incremental.m
@@ -0,0 +1,28 @@
+// RUN: rm -rf %T/cache %T/cache1 %T/cache2 
+//
+// Build B which imports A.
+// RUN: %clang_cc1 -cc1 -fsyntax-only -fmodules -fimplicit-module-maps \
+// RUN:   -fmodules-cache-path=%T/cache -fdisable-module-hash \
+// RUN:   -I %S/Inputs/builtins %s
+// RUN: mv %T/cache %T/cache1
+//
+// Build only A.
+// RUN: echo '@import A;' >%t.m
+// RUN: %clang_cc1 -cc1 -fsyntax-only -fmodules -fimplicit-module-maps \
+// RUN:   -fmodules-cache-path=%T/cache -fdisable-module-hash \
+// RUN:   -I %S/Inputs/builtins %t.m
+//
+// Incrementally build B which imports A.
+// RUN: %clang_cc1 -cc1 -fsyntax-only -fmodules -fimplicit-module-maps \
+// RUN:   -fmodules-cache-path=%T/cache -fdisable-module-hash \
+// RUN:   -I %S/Inputs/builtins %s
+// RUN: mv %T/cache %T/cache2
+//
+// RUN: llvm-bcanalyzer %T/cache1/B.pcm >%t.dump
+// RUN: llvm-bcanalyzer %T/cache2/B.pcm >>%t.dump
+// RUN: cat %t.dump | FileCheck %s
+
+// Verify the identifier table has the same size in both versions of B.pcm:
+// CHECK:  1 [[INDENT_SIZE:[0-9]+]] 100.00 IDENTIFIER_TABLE
+// CHECK:  1 [[INDENT_SIZE]] 100.00 IDENTIFIER_TABLE
+@import B;